The art of surveying involves the determination of unknown positions using measurements of angles and distances. For example, in some surveying operations horizontal and vertical angles and distance are measured between a reference point and a target point.
In other surveying operations, horizontal and vertical angles are measured between a reference point and a target point from more than one position. In either case, the measured data may be used to calculate the location of the target point.
A theodolite is a surveying instrument that is commonly used to measure horizontal and vertical angles. A theodolite typically includes a telescope mounted so that it rotates about horizontal and vertical axes. A theodolite may include circular scales that are used in measuring the angular position of the telescope. The horizontal angle (i.e. yaw) and the vertical angle (i.e. pitch) are read from the circular scales to determine the yaw of the target with respect to a reference position and the pitch of the target with respect to the local gravity vector. Some modern electronic theodolites utilize angle encoders instead of scales to automate angular measurements.
Theodolites frequently include electronic distance measurement (EDM) units to measure the distance from the theodolite to the target. Such integrated systems are commonly referred to as total stations. Total stations generally include a computer or control unit for controlling the measurements and for storing measurement data.
Despite the utility of theodolites and total stations, improved methods and systems for determining angles and locations of points are desired.